Albumin stabilized gold nanostars: a biocompatible nanoplatform for SERS, CT imaging and photothermal therapy of cancer

Plasmonic nanoparticles have emerged as a multifunctional material for biomedical applications. In comparison to other nanostructures, plasmonic gold nanostars with their anisotropic geometry and photophysical properties have gained immense attention. However, their synthesis based on colloid chemistry has always relied on toxic reagents which raise huge concerns for their use in the body. Moreover, lack of stability and functional group for further bioconjugation limited their use. Herein, gold nanostars (GNS) were synthesized using a simple wet chemistry route without the use of any toxic reagents. These nanostars were further functionalized with albumin to impart stability yielding a monodispersed colloidal solution of particles with similar to 120 nm in size. The albumin stabilized gold nanostars (Alb-GNS) tagged with the Raman reporter dye, Rhodamine 6G exhibited a surface enhanced Raman scattering (SERS) property suggesting its potential use for Raman imaging. Alb-GNS exhibited extreme compatibility towards normal (L929) and cancerous (KB) cells with no reactive oxygen species development and hemolytic response towards red blood cells. Additionally, its superior computed tomographic (CT) contrast ability and photothermal activity towards cancer cells bring about Alb-GNS as a single platform for multimodal theragnostic application.